Switching device



Sept. 30, 1958 w. HOPPE\ 2,854,541

SWITCHING DEVICE Filed May 21, 1953 INVENTOR WALTER HOPPE nited StatesPatent SWITCHING DEVICE Walter Hoppe, Yverdon, Switzerland, assignor toEl-Re Ma S. A., Lugano, Switzerland Application May 21, 1953, Serial No.356,577

Claims priority, application Switzerland December 6, 1952 Claims. (Cl,200-87) The present invention relates to a switching device, and moreparitcularly to a switching device for use in electrotechnicalapparatus, more particularly in calculating machines having relays, andcomprises two groups of contact pieces one of which is fixed and theother is movable, one of the groups of contact pieces being arranged fordisplacement with regard to the contact pieces of the other group.

In order to assure a good electrical contact the movable contact pieceshave to exert a sufiicient pressure on the fixed contact pieces withwhich they have to establish the electric contact. This leads torelatively large frictional forces when the movable contact pieces aredisplaced with respect to the fixed contact pieces so that the forcerequired for producing the displacement is great and the wear and tearof the contact pieces is considerable. The strong force required in theknown switching devices for producing the displacement presents aserious drawback when the energy which can be used for producing thedisplacement is limited.

It is an object of the present invention to avoid these drawbacks.

Other objects and advantages will be apparent from a consideration ofthe specification and claims.

A contacting device according to the present invention comprises incombination a group of fixed contact pieces, a group of movable contactpieces, the contact pieces of one of the groups being displaceable withrespect to the contact pieces of the other group so that at least one ofthe movable contact pieces is opposite to at least one predeterminedcontact piece of the fixed contact group, the contact pieces of at leastone of the groups consisting at least partly of magnetic material, andan electric coil arranged so as to surround the contact piecesconsisting of magnetic material, the electric coil causing by theenergization thereof an attraction of at least one of the movablecontact pieces toward the fixed contact piece being opposite thereto soas to establish a firm electrical contact therebetween.

The accompanying drawing shows schematically and by way of example twoembodiments of the present invention.

In the drawings Fig. 1 is a side view of a first embodiment of theinvention;

Fig. 2 is a section taken along the line IIII of Fig. 1;

Fig. 3 is a plan view of a second embodiment of the invention; and

Fig. 4 is a section taken along the line IV-lV of Fig. 3.

Referring now to the drawings and first to Figs. 1 and 2, the contactingdevice comprises a group of nine fixed contact pieces 1 which arecarried by an insulating body 3 as more fully described hereinafter, anda group of three movable contact pieces 2 which are arranged in recessesof an insulating body 4. The latter is connected with two rods 5 by tworesilient rings 6, respectively, the rods 5 sliding in bores provided inthe body 3. The body 4 and contact pieces 2 supported by the same arethus capable of displacement with respect to the contact pieces 1 andthe body 3 by means of a longitudinal movement of the rods 5.

Each movable contact piece 2 is provided with a cen tral rod-likeportion 7 which traverses the body 4 and is provided with a groove 10near the extremity thereof. The ends of the portions 7 are soldered torespective connecting wires (not shown). The upper parts of the portions7 traverse helicoidal springs 8, respectively, which abut against thebody 4, and a resilient annulus 9 arranged in each of the grooves 10 ofthe portions 7. The springs 8 have the task of urging the movablecontact pieces 2 associated therewith into positions in which they arekept at a distance from the fixed contact pieces 1.

Referring now to Fig. 2 it is seen that the fixed contact pieces 1consist of U-shaped lamellae which are partly embedded in the insulatingbody 3. These lamellae consist of magnetic material and have midportions surrounded by an electric coil 12. Each lamella forms thus apart of a magnetic circuit for the coil 12 and serves at the same timeas an electrical contact piece. To this effect each lamella 1 isprovided with an extension 11 which allows to connect to it a connectingwire (not shown) by soldering. Each movable contact piece 2 has thegeneral form of a plate and consists also of magnetic material so thatthe assembly of a fixed contact piece and a movable contact piece formsan elementary magnetic circuit comprising two air gaps.

The operation of this device is as follows:

As long as the coil 12 is not connected to a voltage source the movablecontact pieces 2 are held apart from the fixed contact pieces 1 by theaction of the springs In consequence thereof it is possible to displacethe body 4 and thus the movable contact pieces with regard to the fixedcontact pieces 1 without having to overcome the friction between thecontact pieces of one group and those of the other group; therefore, theenergy necessary for producing these displacements is as low aspossible. When the movable contact pieces 2 have been brought inopposition to the desired fixed contact pieces 1 the coil 12 is putunder voltage so that a magnetic field results which provokes theattraction of the movable contact pieces 2 which are displaced parallelto the principal plane thereof and in direction of the fixed contactpieces 1. The electrical contact established between the fixed andmovable contact pieces is stable and lasts as long as the coil 12 isexcited.

The surfaces which make contact with one another are preferably coveredby a layer of non-magnetic material such as silver having goodelectrical conductive proper-' ties in order to assure a good contactand to diminish the remanence of the magnetic circuit. This layer can beapplied for instance by electrolysis, by hot spray metallization, or bysoldering. The contact surfaces of certain contact pieces, for instancethe movable contact pieces, can be slightly rounded as indicated at 13in order to produce a concentration of the magnetic flux and thus toobtain an elevated contact pressure.

In another embodiment of the invention the contact pieces 2 are fixedlyembedded in the insulating body 4 and movable contact pieces 1 aredisposed within the insulating body 3. As soon as the coil 12 is excitedthe contact pieces 1 are displaced toward the contact pieces 2. Thecontact pieces 1 can be maintained at a distance from the movablecontact pieces by means of one or several resilient elements or simplyby their own weight.

In a contact device such as shown in Figs. 1 and 2, I may also omit thesprings 8 returning the contact pieces 2 to the original positionthereof. Thus the latter would continually rest on the contact pieces 1;however, as the weight thereof is very slight the supplemental frictionresulting therefrom would be exceedingly weak. Such an arrangement couldobviously only be adopted in a plant the operation of which is notimpeded by the contact which are produced between the fixed contactpieces and the movable contact pieces during the lateral displacement ofthe latter. The arrangement according to Figs. 1 and a scess.

2 could also be mounted so that the contact pieces 2 are below thecontact pieces 1. In this way, it is possible to omit the springs 8, thecontact pieces 2 being held by their own weight in a position away fromthe contact pieces 1.

In the embodiment shown in Figs. 3 and 4: the movable contact pieceshave the form .ofthin plates 14 consisting. of magnetic material andarranged on a sectorv 2.5 of insulating material in prolongation ofthcradii thereof. The sector 15 is pivotable about the-shaft 16. The fixedcontact pieces are formed each by two substantially U shaped parts 17.Each, of the parts .17 is attached to one extremity of a leaf spring,18, The two leaf springs 18 are attached to a block 19 consisting ofinsulating material and are electricallyconnected:to each other by meansof a rivet 21. The current can be; led into the portions 17.advantageously by means, of connecting Wires (not shown) attachedtoone'of the leaf springs 13. A con necting wire. (not shown) iselectrically connected to each of themovable contacts. Thetwoportionslfl are so held by the leaf springs-18y that the outer ends oftheir branches are disposed-opposite to. each other and form betweenthemselves two air gaps. The plates Iut are. capable of being arrangedin one of the air gaps, whereas the branches of the portions-17 whichform the other air gaps are surrounded by a: coil 20. When the coil 20is fed with a current the two portions It? are attracted toward eachother by the magnetic field which is produced, and'the plate 1 lisheldbetweenthetwo per tions 17. From this results an excellentelectricalcontact between the portions 17 and theplate 14-. When the coil Ztl isnot excited, the two portions .17 move away from each other and it ispossible to displace the movable contact pieces 14 betweengthe two;portions. 17 of the fixed contact pieces-by rotating. the shaft 16.

Also in this embodiment thesurfaces which come into contact with oneanother are covered bya material having a good electrical conductivitysuch as silver. In a further modificationthe plates14-consist ofnon-magnetic material having; a good; conductivity, for instance copper.

The embodiments which havebeen described hereinabove have as their mainadvantage. that the displace ment of the movable contact. piecesisetfected without any other effort besides that exerted by the forcesof friction of their support and. the. forces of inertia. The forces offriction-of the movablecontact pieces against the fried contact pieceswhichusuallyplay the greatest part in the known contacting-devices arehere practically eliminated. At-the same time .the wear ofthe contactfaces due. to the frictionat the. displacement thereof is alsoeliminated. The safety of the contact is very large because in each casea double contact is formed and the contact pressure is high. The latteris: in fact due to the attracting force of the magnets which isdiminished only by the force of retraction of: the springs which,however, is relatively weak.

It is to be understood thatthe. number of the contact pieces of eachgroup may be different from those indicated in the embodiments describedhereinabove; particularly, contact devices can be. provided-whichcomprise only one movable contact piece which cooperates with aplurality of fixed contact pieces.

While I have illustrated and described the invention as embodied in aswitching device-for calculating machines, Ido not intend to be limitedto the details shown, since various modifications andstructural changesmay be made without departing in anyway from the spirit of my invention.

What I claim is:

1. An electrical switching devicecomprising in combination, a stationaryinsulating body'having a plurality of recesses; a group of fixed contactpieces arranged, respectively, in said recesses, each of said fixedcontact pieces being constituted bya U-shaped lamella of magneticmaterial; electric coil means surrounding at least partly said fixedcontact pieces; and at least one movable contact piece consisting atleast partly of magnetic material, said movable contact piece beingdisplaceable into at least two positions opposite to and spaced fromsaid fixed contact pieces so as to selectively make contact therewith onenergization of said coil means.

2. An electrical switching device comprising two insulating bodieshaving opposite conforming faces, one of said bodies being stationaryand provided with supports for the other body, said other body beinglongitudinally displaceable with respect to said stationary body, magnetic material containingcontact pieces in equally and uniformly spacedrelationship in said opposite faces of said insulating bodies, bores inthe displaceable insulating body, the contact pieces of saiddisplaceable insulating body consisting of plates provided with rod-lileextensions engaging said bores, the contact pieces-in thev stationaryinsulating body consisting of a plurality o superposed U-shapedlamellac, and electric coil means at least partly surrounding saidsuperposed lamellae.

3. An electrical switching device comprising two insulating bodieshaving opposite conforming faces in closely spaced relationship, one ofsaidbodics being stationary and provided with supports for the otherbody. said other body being longitudinally displaccable with rc spect tosaid stationary body, magnetic material contaia ing contact pieces inequally and uniformly spaced relationship in said opposite facesof saidinsulating bodies. bores in the-displaceable insulating body, thecontact pieces of said displaceablc insulating body consisting of platesprovided with rod-likeextension slidably engaging said bores, thecontact pieces inthe stationary insulating body consisting of aplurality of superposed U-shapcd lamellae, electric coil means at leastpartly surrounding said superposed lamella, and spring means normallyholding the contact pieces of the displaceable insulating body at adistance from the contact pieces of the stationary insulating body,contact being established on euergization of said coil means.

4. An electrical contact device comprising a. stationary insulatingbody, a group offixedicontact pieces in said body, a movable insulatingbody slidably arranged for displacement ina plane parallelto'said-stationary body in closely spaced relationship thereto, a groupof magnetic contact pieces in saidrnovable body, said latter contactpiecesbeing movableat right angles to said plane and selectivelyplaceable inopposition to the contact pieces of said stationary body. bydisplacement of said movable body, and electric coil means in said,stationary body surrounding said group of fixed contact pieces. saidelectric coil means causing on-energization thereof attraction betweensaid opposite fixed and movable con tact pieces and establishing a firmelectric contact there between.

5. An electrical contact device as defined in claim 4 wherein said groupof fixed contact pieces contains a greater number of contact pieces thansaidgroup of movable contact pieces.

References (Iited in the file of this patent UNITED STATES PATENTS515,108 Callender Feb. 20, 1894 537,412 Fyfe Apr. 9, 1895 1,709,212Green Apr. 16, 1929 1,769,674 Brandt July I, 1930 1,795,787 MattinglyMar. 10, 1931 1,858,562 Schedlbauer May 17, 1932 1,876,295 HofgaardSept. 6, 1932 2,510,700 Lamb June 6,

FOREIGN PATENTS 555,840 Germany Aug. 6, 1932 583,669 Great Britain Dec.24, 1946

